High sensitivity satellite positioning system receiver

ABSTRACT

An attenuated satellite positioning system (SPS) signal is acquired using long integration over multiple navigation data bits. To produce a stable internal clock signal to perform the long integration, an external clock signal is received from a highly stable source, such as a wireless communication base station or a nearby femtocell. An internal oscillator is driven at a desired frequency that is aligned with the scaled frequency of the external clock signal to produce the stable internal clock signal. The SPS signal is received and integrated for an extended period using the internal clock signal. Predicted SPS data may be received from an external source and used to perform coherent integration. Alternatively, non-coherent integration may be performed. Additionally, a motion sensor may be used to determine if there is motion relative to the external clock source or to compensate for Doppler errors in the external clock signal due to motion.

BACKGROUND

Obtaining accurate position information for mobile stations, such ascellular or other wireless communication devices, is becoming prevalentin the communications industry. Satellite positioning systems (SPS's)such as, for example, the Global Positioning System (GPS) offers anapproach to providing wireless position determination. An SPS user canderive precise navigation information including three-dimensionalposition, velocity and time of day through information gained fromsatellite vehicles (SVs) in orbit around the earth. The signals that arereceived from the SVs are typically rather weak. Therefore, in order todetermine the position of the receiver, the receiver must besufficiently sensitive to receive these weak signals and interpret theinformation that is represented by them.

One limitation of current SPS receivers is that their operation islimited to situations in which multiple satellites are clearly in view,without obstructions, and where a good quality antenna is properlypositioned to receive such signals. SPS signals are severely attenuatedin an indoor environment or other areas that suffer from blockageconditions, e.g., with significant foliage or urban canyons.Consequently, determining a position using SPS in environments withblockage conditions or generally weak signals is difficult.

SUMMARY

A device with a satellite positioning system (SPS) receiver and awireless receiver acquires a weak or attenuated SPS signal using longintegration over multiple navigation data bits. To produce a stableclock signal to perform the long integration, an external clock signalis received from a highly stable source such as a wireless communicationbase station, NTP/PTP (network time protocol, precise time protocol)delivered, e.g., over Ethernet backhaul, or a nearby femtocell. Aninternal oscillator is driven at a desired frequency that is alignedwith the scaled frequency of the external clock signal to produce thestable internal clock signal. The SPS signal is received and integratedfor an extended period using the internal clock signal. For example, areceived SPS signal may be integrated over multiple navigation data bitsusing the internal clock at the desired frequency when, e.g., the deviceis stationary. Predicted SPS data may be received from an externalsource, e.g., through an Ethernet backhaul, and used to perform coherentintegration. Alternatively, non-coherent integration may be performed.Additionally, a motion sensor may be used to determine if there ismotion relative to the external clock source or to compensate forDoppler errors in the external clock signal due to motion.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates a system including a device with a satellitepositioning system (SPS) receiver that is capable of tracking a weak orcompromised SPS signal.

FIG. 2 is a flow chart illustrating a method of tracking a weak orcompromised SPS signal.

FIG. 3 is a block diagram of an embodiment of the device, which may beused to track an attenuated SPS signal.

DETAILED DESCRIPTION

FIG. 1 illustrates an example of a system 10 including a device 100 witha satellite positioning system (SPS) receiver 120 that is capable oftracking a weak or compromised SPS signal. FIG. 2 is a flow chartillustrating a method of tracking a weak or compromised SPS signal,e.g., with system 10. The device 100 illustrated in FIG. 1 may determineits position and/or be used for navigation based on, e.g., determiningits latitude and longitude using signals from a satellite positioningsystem (SPS), which includes satellite vehicles 102. To achieve therequired processing gain to acquire and track a weak SPS signal, thedevice 100 integrates the SPS for an extended period of time,illustrated schematically in FIG. 1 as long integration block 157.System 10 resolves several factors that limit length of integration ofthe SPS signal, including clock stability, knowledge of the SPSencoding, and user motion.

A satellite positioning system (SPS) typically includes a system oftransmitters positioned to enable entities to determine their locationon or above the Earth based, at least in part, on signals received fromthe transmitters. Such a transmitter typically transmits a signal markedwith a repeating pseudo-random noise (PN) code of a set number of chipsand may be located on ground based control stations, user equipmentand/or satellite vehicles. In a particular example, such transmittersmay be located on Earth orbiting satellite vehicles (SVs) 102,illustrated in FIG. 1. For example, a SV in a constellation of GlobalNavigation Satellite System (GNSS) such as Global Positioning System(GPS), Galileo, Glonass or Compass may transmit a signal marked with aPN code that is distinguishable from PN codes transmitted by other SVsin the constellation (e.g., using different PN codes for each satelliteas in GPS or using the same code on different frequencies as inGlonass).

In accordance with certain aspects, the techniques presented herein arenot restricted to global systems (e.g., GNSS) for SPS. For example, thetechniques provided herein may be applied to or otherwise enabled foruse in various regional systems, such as, e.g., Quasi-Zenith SatelliteSystem (QZSS) over Japan, Indian Regional Navigational Satellite System(IRNSS) over India, Beidou over China, etc., and/or various augmentationsystems (e.g., an Satellite Based Augmentation System (SBAS)) that maybe associated with or otherwise enabled for use with one or more globaland/or regional navigation satellite systems. By way of example but notlimitation, an SBAS may include an augmentation system(s) that providesintegrity information, differential corrections, etc., such as, e.g.,Wide Area Augmentation System (WAAS), European Geostationary NavigationOverlay Service (EGNOS), Multi-functional Satellite Augmentation System(MSAS), GPS Aided Geo Augmented Navigation or GPS and Geo AugmentedNavigation system (GAGAN), and/or the like. Thus, as used herein an SPSmay include any combination of one or more global and/or regionalnavigation satellite systems and/or augmentation systems, and SPSsignals may include SPS, SPS-like, and/or other signals associated withsuch one or more SPS.

The device 100 is not limited to use with an SPS for positiondetermination, as position determination techniques described herein maybe implemented in conjunction with various wireless communicationnetworks, including cellular towers 104 and from wireless communicationaccess points 106, such as a wireless wide area network (WWAN), awireless local area network (WLAN), a wireless personal area network(WPAN), and so on. Further the device 100 may access online servers toobtain data, such as satellite images, using various wirelesscommunication networks via cellular towers 104 and from wirelesscommunication access points 106, or using satellite vehicles 102 ifdesired. The terms “network” and “system” are often usedinterchangeably. A WWAN may be a Code Division Multiple Access (CDMA)network, a Time Division Multiple Access (TDMA) network, a FrequencyDivision Multiple Access (FDMA) network, an Orthogonal FrequencyDivision Multiple Access (OFDMA) network, a Single-Carrier FrequencyDivision Multiple Access (SC-FDMA) network, a Long Term Evolution (LTE)network, a WiMAX (IEEE 802.16) network, and so on. A CDMA network mayimplement one or more radio access technologies (RATs) such as cdma2000,Wideband-CDMA (W-CDMA), and so on. Cdma2000 includes IS-95, IS-2000, andIS-856 standards. A TDMA network may implement Global System for MobileCommunications (GSM), Digital Advanced Mobile Phone System (D-AMPS), orsome other RAT. GSM and W-CDMA are described in documents from aconsortium named “3rd Generation Partnership Project” (3GPP). Cdma2000is described in documents from a consortium named “3rd GenerationPartnership Project 2” (3GPP2). 3GPP and 3GPP2 documents are publiclyavailable. A WLAN may be an IEEE 802.11x network, and a WPAN may be aBluetooth network, an IEEE 802.15x, or some other type of network. Thetechniques may also be implemented in conjunction with any combinationof WWAN, WLAN and/or WPAN.

Referring to the flow chart of FIG. 2, in order to acquire an SPS signalusing long integration, the device 100 receives an external clock signal(202). To integrate the SPS signal for an extended length of time, theinternal clock 153 of the device 100 should remain stable over theperiod of integration time, to ensure that the signal search isperformed in the correct time-frequency bin. The internal clock 153 ofmost commercial devices, however, uses a low cost oscillator, whichgenerally does not have the clock frequency stability required for longintegration. Thus, to generate a stable clock signal, device 100 uses awireless receiver 130 to receive a highly accurate external clock signalfrom, e.g., wireless communication base stations 104 (e.g., CDMA basestation, GSM/WCDMA base station), wireless access points 106, or a wiredsignal such as NTP/PTP (network time protocol, precise time protocol)delivered via an Ethernet backhaul at wired communication interface 135in FIG. 1, or a pilot signal from a nearby femtocell. The external clocksignal is provided to a frequency controller 155 that determines thefrequency of the external clock signal (204) and scales the externalclock frequency to the desired frequency (206). The scaled externalclock signal is used to drive an oscillator in the internal clock 153 sothat the frequency of the internal clock 153 is aligned with the moreaccurate scaled external clock signal (208).

The device 100 receives a severely attenuated SPS signal from thesatellite vehicles 102 (210). The attenuated SPS signal may be due toblockage conditions, such as found in indoor environments. To improvereception performance, the device 100 integrates the SPS signal for anextended period of time using the modified internal clock signal (214).The integration may be performed coherently or non-coherently.

System 10 may enable coherent integration of the SPS signal bypredicting SPS data, including the navigation data bits, and providingthe predicted SPS data in the form of SPS sensitivity assistance data tothe device 100 (211). As is well known in the art, SPS signals aretypically encoded using meander coding, Forward Error Correction (FEC)coding, convolutional coding, and/or the like. In order to coherentlyintegrate the SPS signal for an extended period, the device 100 mustdecode the SPS signal. However, because device 100 has not locked ontothe signal, device 100 cannot detect information within the SPS signalitself to assist in decoding, such as the navigation data bit.Accordingly, system 10 detects the SPS signal at a location external tothe device 100 where the SPS signal is stronger. Based on the receivedSPS signal, SPS data is predicted and provided in the form of a SPSsensitivity assistance signal to the device 100. The predicted SPS datamay be used by the device 100, for example, to wipe-off the navigationdata modulated onto a SPS spreading signal, which permits an extendedcoherent integration beyond the duration of the transmitted data symbolof the SPS signal (e.g., greater than 20 ms) thereby improvingsensitivity. The use of SPS sensitivity assistance is described ingeneral in U.S. App. No. 2010/0013702, entitled “Methods and ApparatusesFor Requesting/Providing Sensitivity Assistance Information Associatedwith Various Satellite Positioning Systems in Wireless CommunicationNetworks”, by Lin et al., filed Jul. 10, 2009, having the same assigneeas the present application and which is incorporated herein byreference.

For example, as illustrated in FIG. 1, system 10 includes a locationserver 50, which includes a position determination module 52. Thelocation server 50 is intended to represent one or more devices and/orone or more specific apparatuses therein that is/are enabled to support,at least in part, such position determination processes. The locationserver 50 may communicate directly and/or indirectly with device 100using one or more wired (e.g., Ethernet backhaul) and/or one or morewireless communication links (e.g., wireless communication base stations104). Hence, in certain example implementations, a location server 50may take the form of and/or otherwise operatively comprise one or morewireless transmitters, receivers, transceivers, one or more basestations, various wired and/or wireless network resources, one or morecomputing devices enabled as specific apparatuses, and/or other likecomputing and/or communication devices. The location server 50 mayprovide solicited or unsolicited SPS sensitivity assistance data todevice 100.

The location server 50 receives the SPS signals from satellitepositioning system (SPS), which includes satellite vehicles 102. As iswell known, the SPS signals may include navigation information signalsand other information signals that are transmitted by an SPS in a nativeformat. Based on at least part of the received SPS signal, the positiondetermination module 52 predicts SPS data and produces an SPSsensitivity assistance signal. Techniques for predicting such SPS dataare well known and is described, e.g., in U.S. Pat. No. 6,775,802,entitled “Method, Apparatus, and System for Signal Prediction”, by PeterGaal, having the same assignee as the present application and which isincorporated herein by reference. The SPS sensitivity assistance signalis transmitted by the location server 50 directly and/or indirectly tothe device 100. The SPS sensitivity assistance signal may include a timemark, which may be used by the device 100 to compensate for delay in thereception of the SPS sensitivity assistance signal by the device 100.The device 100 may use the received SPS sensitivity assistance signal toassist in the acquisition of the actual SPS signal(s), e.g., employingmodulation wipe-off techniques which may significantly increase thesensitivity of an SPS receiver. For example, the SPS sensitivityassistance signal may include navigation data bit information which isused to modulate an SPS signal. With knowledge of the navigation databit, the device 100 can wipe-off the navigation data modulation,permitting coherent integration over multiple navigation data bits,which may be up to 30 s to 120 s or longer.

If desired, non-coherent integration may be performed over an extendedtime period, which obviates the need for the predicted SPS data in theSPS sensitivity assistance signal (211) and, thus, location server 50 insystem 10 (FIG. 1). Non-coherent integration may be performed, e.g., bysquaring the SPS signal, which eliminates the navigation data modulatedonto the SPS signal. While non-coherent integration simplifies thesystem 10 by eliminating the need for location server 50, squaring theSPS signal also reduces the signal to noise ratio (SNR), and thus, mayrequire increased integration time relative to the coherent integrationdescribed above.

Another factor that limits the length of integration is motion of thedevice 100. If the device 100 is substantially stationary, extendedintegration may be performed because the frequency search windows,satellite movement, Doppler errors due to unknown user dynamics, etc.,may be more predictable than if the device is moving, particularly athigher rates of speed. Thus, motion of the device 100 may be detected(212), e.g., using motion/inertial sensors 140, such as accelerometers,magnetometers, and/or gyroscopes, which provides motion related data tothe device 100. In one embodiment, device 100 may only conduct searchesfor a SPS signals using long integration times, when the motion/inertialsensors 140 indicate that the device 100 is stationary. Alternatively,if desired, the motion of the device 100 as determined from themotion/inertial sensors 140 may be used to compensate for any Dopplererrors caused by movement of the device 100 with respect to the sourceof the external clock signal during a search for SPS signals. Of course,where the device 100 is stationary or substantially stationary, forexample, when the device 100 is a wireless access point, femtocell orother such device, motion detection (212) may not be necessary,obviating the need for motion/inertial sensors 140.

The device 100 in system 10 may be any device capable of receiving SPSsignals as well as an external clock signal. The device 100 may bestationary or semi-stationary (e.g., a femtocell or access point), or amobile station, for example. As used herein, a mobile station (MS)refers to a device such as a cellular or other wireless communicationdevice, personal communication system (PCS) device, personal navigationdevice (PND), Personal Information Manager (PIM), Personal DigitalAssistant (PDA), laptop or other suitable mobile device which is capableof receiving wireless communication and/or navigation signals, such asnavigation positioning signals. The term “mobile station” is alsointended to include devices which communicate with a personal navigationdevice (PND), such as by short-range wireless, infrared, wirelineconnection, or other connection—regardless of whether satellite signalreception, assistance data reception, and/or position-related processingoccurs at the device or at the PND. Also, “mobile station” is intendedto include all devices, including wireless communication devices,computers, laptops, etc. which are capable of communication with aserver, such as via the Internet, Wi-Fi, or other network, andregardless of whether satellite signal reception, assistance datareception, and/or position-related processing occurs at the device, at aserver, or at another device associated with the network. Any operablecombination of the above are also considered a “mobile station.”

FIG. 3 is a block diagram of an embodiment of the device 100, which maybe used to track an attenuated SPS signal. The device 100 may include asatellite positioning system (SPS) receiver 120 that receives signalsfrom SPS satellites 102 (FIG. 1) via antenna 124. Device 100 may alsoinclude a wireless receiver 130, which may be, e.g., a wireless networkradio transceiver that is capable of sending and receivingcommunications to and from wireless access point 106 and/orcommunications to and from wireless communication base stations 104(e.g., CDMA base station, GSM/WCDMA base station) via antenna 124 or aseparate antenna. The device 100 may also include an optional wiredcommunication interface 135, e.g., for sending and receiving signals viaEthernet or other wired format. The device 100 may also includemotion/inertial sensors 140, which may include, e.g., an accelerometer,gyroscopes, magnetometers or other appropriate device, such as a vehicleodometer or wheel tick sensor, e.g., where device is on a vehicle. Themotion/inertial sensors 140 may assist in the determination of motion,e.g., direction and change in position with respect to the source of theexternal clock signal.

SPS receiver 120, wireless transceiver 130 and motion/inertial sensors140, if used, can be coupled to and communicate with a control unit 150.The control unit 150 may accept and process data from SPS receiver 120,wireless transceiver 130, and motion/inertial sensors 140 and controlthe operation of the device. The control unit 150 may be provided by aprocessing unit 152 and associated memory 154, and may include supporthardware 156, software 158, and firmware 157. It will be understood asused herein that the processing unit 152 can, but need not necessarilyinclude, one or more microprocessors, embedded processors, controllers,application specific integrated circuits (ASICs), digital signalprocessors (DSPs), and the like. The term control unit is intended todescribe the functions implemented by the system rather than specifichardware. Moreover, as used herein the term “memory” may refer to anytype of computer storage medium, including long term, short term, orother memory associated with the device, and is not to be limited to anyparticular type of memory or number of memories, or type of media uponwhich memory is stored.

The control unit 150 includes a frequency controller 155, illustratedhere as a phase-locked loop (PLL) and an internal clock 153, illustratedhere as a variable oscillator in the PLL. The frequency controller 155may receive the external clock signal via wireless transceiver 130,which may serve as the input signal to the PLL. As is well known in theart, the input signal of the PLL is compared to the output signal of thePLL in a negative feedback loop using a phase detector. The outputsignal of the phase detector controls internal clock 153, e.g., variableoscillator. Internal clock 153 may be coupled to processing unit 152. Asillustrated, the feedback path includes a frequency divider 157, whichmay be used to functionally scale the frequency of the external clocksignal. Of course, if desired, other methodologies/circuits may be usedto scale the external clock signal and control the internal clock 153,such as a frequency-locked loop and/or a frequency synthesizer. By wayof example, U.S. Pat. No. 6,928,275, entitled “Method and Apparatus forCompensating Local Oscillator Frequency Error”, by Patrick, et al.,having the same assignee as the present application and which isincorporated herein by reference, describes techniques for controllingthe local oscillator error.

The control unit 150 may also include an integration control unit 159which is illustrated separately from processing unit 152 for clarity,but may be within the processing unit 152. The integration control unit159 performs the long integration, either coherently or non-coherently,as discussed above. For the coherent integration, the control unit 150receives the SPS sensitivity assistance with the predicted SPS data viewwireless transceiver 130, with which the processing unit 152 may employ,e.g., modulation wipe-off techniques. The integration control unit 159may then perform coherent integration for an extended time on theresulting SPS signal. As discussed above, if desired, non-coherentintegration may be performed without requiring an SPS sensitivityassistance signal.

The device 100 may also include a user interface 160 that is incommunication with the control unit 150, e.g., the control unit 150accepts data from and controls the user interface 160. The userinterface 160 may include a display 162 that may display control menusand positional information. The user interface 160 may further include akeypad 164 or other input device through which the user can inputinformation into the device 100. In one embodiment, the keypad 164 maybe integrated into the display 162, such as a touch screen display. Theuser interface 160 may also include, e.g., a microphone and speaker,e.g., when the device 100 is a cellular telephone.

The methodologies described herein may be implemented by various meansdepending upon the application. For example, these methodologies may beimplemented in hardware, firmware, software, or any combination thereof.For a hardware implementation, the processing units may be implementedwithin one or more application specific integrated circuits (ASICs),digital signal processors (DSPs), digital signal processing devices(DSPDs), programmable logic devices (PLDs), field programmable gatearrays (FPGAs), processors, controllers, micro-controllers,microprocessors, electronic devices, other electronic units designed toperform the functions described herein, or a combination thereof.

For a firmware and/or software implementation, the methodologies may beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. Any machine-readable mediumtangibly embodying instructions may be used in implementing themethodologies described herein. For example, code (e.g., software code)may be stored in memory 154 and executed by processing unit 152. Memorymay be implemented within the processing unit or external to theprocessing unit. As used herein the term “memory” may refer to any typeof long term, short term, volatile, nonvolatile, or other memory and isnot to be limited to any particular type of memory or number ofmemories, or type of media upon which memory is stored.

If implemented in firmware and/or software, the functions may be storedas one or more instructions or code on a computer-readable medium.Examples include computer-readable media encoded with a data structureand computer-readable media encoded with a computer program.Computer-readable medium may take the form of an article of manufacture.Computer-readable media include physical computer storage media. Astorage medium may be any available medium that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, flash memory, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer; disk and disc, as used herein, includes compactdisc (CD), laser disc, optical disc, digital versatile disc (DVD),floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically, e.g., with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

In addition to storage on computer-readable medium, instructions and/ordata may be provided as signals on transmission media included in acommunication apparatus. For example, a communication apparatus mayinclude a transceiver having signals indicative of instructions anddata. The instructions and data are configured to cause one or moreprocessing units to implement the functions outlined in the claims. Thatis, the communication apparatus includes transmission media with signalsindicative of information to perform disclosed functions. At a firsttime, the transmission media included in the communication apparatus mayinclude a first portion of the information to perform the disclosedfunctions, while at a second time the transmission media included in thecommunication apparatus may include a second portion of the informationto perform the disclosed functions.

Although the present invention is illustrated in connection withspecific embodiments for instructional purposes, the present inventionis not limited thereto. Various adaptations and modifications may bemade without departing from the scope of the invention. Therefore, thespirit and scope of the appended claims should not be limited to theforegoing description.

What is claimed is:
 1. A method of acquiring a satellite positioningsystem (SPS) signal with a substantially stationary or semi-stationarydevice, the method comprising: receiving an external clock signal at thesubstantially stationary or semi-stationary device through a wiredinterface; driving an oscillator to a desired frequency that is alignedwith a scaled frequency of the external clock signal to generate aninternal clock signal; receiving an SPS signals; receiving predicted SPSdata comprising SPS sensitivity assistance data through the wiredinterface; and integrating the received SPS signal over multiplenavigation data bits using the internal clock signal to acquire the SPSsignal, wherein the received SPS signal is coherently integrated usingthe received predicted SPS data.
 2. The method of claim 1, wherein thereceived predicted SPS data includes a predicted value of navigationdata bits in the SPS data, the method further comprising performing adata wipe-off of the received SPS signal using the predicted value ofthe navigation data bits.
 3. The method of claim 1, wherein thepredicted SPS data is received through an Ethernet backhaul.
 4. Asubstantially stationary or semi-stationary device comprising: asatellite positioning system (SPS) signal receiver that providespositioning data for the substantially stationary or semi-stationarydevice; a wired interface that receives an external clock signal; aninternal clock; a frequency controller coupled to the internal clock andthe wired interface, the frequency controller driving the internal clockto a desired frequency that is aligned with a scaled frequency of theexternal clock signal; a processor connected to the SPS signal receiverand the wired interface, and configured to receive a signal from theinternal clock; memory connected to the processor; and software held inthe memory and run in the processor to cause the processor to integratea received SPS signal over multiple navigation data bits using theinternal clock at the desired frequency, wherein predicted SPS datacomprising SPS sensitivity assistance data is received by the wiredinterface that is coupled to the processor, the software further causesthe processor to coherently integrate the received SPS signal using thepredicted SPS data.
 5. The device of claim 4, wherein the predicted SPSdata includes a predicted value of navigation data bits in the SPS data,the software further causes the processor to perform a data wipe-off ofthe received SPS signal using the predicted value of the navigation databits.
 6. The device of claim 4, wherein the frequency controller is aphase-locked loop.
 7. A substantially stationary or semi-stationarydevice comprising: means for receiving an external clock signal at thesubstantially stationary or semi-stationary device through a wiredinterface; means for driving an internal oscillator to a desiredfrequency that is aligned with a scaled frequency of the external clocksignal to generate an internal clock signal; means for receiving asatellite positioning system (SPS) signal; means for receiving predictedSPS data comprising SPS sensitivity assistance data through the wiredinterface; and means for integrating the received SPS signal overmultiple navigation data bits using the internal clock signal to acquirethe SPS signal, wherein the received SPS signal is coherently integratedusing the received predicted SPS data.
 8. The system of claim 7, furthercomprising means for performing a data wipe-off of the received SPSsignal using the predicted SPS data.
 9. A computer-readable storagemedium including program code stored thereon, comprising: program codeto integrate a received SPS signal over multiple navigation data bitsusing an internal clock that is driven at a desired frequency based onan external clock signal received through a wired communicationinterface of a substantially stationary or semi-stationary device,wherein the received SPS signal is coherently integrated using receivedpredicted SPS data comprising SPS sensitivity assistance data.
 10. Amethod of acquiring a satellite positioning system (SPS) signal with asubstantially stationary or semi-stationary device, the methodcomprising: receiving an external clock signal with the substantiallystationary or semi-stationary device via a wired communicationinterface; using the external clock signal to generate an internal clocksignal; receiving an SPS signals; receiving predicted SPS datacomprising SPS sensitivity assistance data via the wired communicationinterface; and integrating the received SPS signal over multiplenavigation data bits using the internal clock signal to acquire the SPSsignal, wherein the received SPS signal is coherently integrated usingthe received predicted SPS data.
 11. The method of claim 10, wherein thereceived predicted SPS data includes a predicted value of navigationdata bits in the SPS data, the method further comprising performing adata wipe-off of the received SPS signal using the predicted value ofthe navigation data bits.
 12. The method of claim 10, wherein theexternal clock signal and the predicted SPS data are received through anEthernet backhaul.
 13. The method of claim 10, wherein the externalclock signal is a NTP/PTP (network time protocol, precise time protocol)signal delivered over an Ethernet backhaul.
 14. A substantiallystationary or semi-stationary device comprising: a satellite positioningsystem (SPS) signal receiver that provides positioning data at thesubstantially stationary or semi-stationary device; a wiredcommunication interface that receives an external clock signal; acontroller coupled to the wired communication interface, the controllergenerating an internal clock signal based on the external clock signal;a processor connected to the SPS signal receiver and the wiredcommunication interface, and configured to receive the internal clocksignal; memory connected to the processor; and software held in thememory and run in the processor to cause the processor to integrate areceived SPS signal over multiple navigation data bits using theinternal clock signal, wherein predicted SPS data comprising SPSsensitivity assistance data is received by the wired communicationinterface that is coupled to the processor, the software further causesthe processor to coherently integrate the received SPS signal using thepredicted SPS data.
 15. The device of claim 14, wherein the predictedSPS data includes a predicted value of navigation data bits in the SPSdata, the software further causes the processor to perform a datawipe-off of the received SPS signal using the predicted value of thenavigation data bits.
 16. The device of claim 14, wherein the controllercomprises a frequency controller that is a phase-locked loop coupled toan internal clock, wherein the frequency controller drives the internalclock to a desired frequency that is aligned with a scaled frequency ofthe external clock signal to produce the internal clock signal.
 17. Thedevice of claim 14, wherein the external clock signal is a NTP/PTP(network time protocol, precise time protocol) signal delivered over anEthernet backhaul.
 18. A substantially stationary or semi-stationarydevice comprising: means for receiving an external clock signal at thesubstantially stationary or semi-stationary device over an Ethernetbackhaul; means for using the external clock signal to generate aninternal clock signal; means for receiving a satellite positioningsystem (SPS) signal; means for receiving predicted SPS data comprisingSPS sensitivity assistance data over the Ethernet backhaul; and meansfor integrating the received SPS signal over multiple navigation databits using the internal clock signal to acquire the SPS signal, whereinthe received SPS signal is coherently integrated using the receivedpredicted SPS data.
 19. The system of claim 18, further comprising meansfor performing a data wipe-off of the received SPS signal using thepredicted SPS data.
 20. A computer-readable storage medium includingprogram code stored thereon, comprising: program code to integrate areceived SPS signal over multiple navigation data bits using an internalclock that is generated based on an external clock signal received overan Ethernet backhaul of a substantially stationary or semi-stationarydevice, wherein the received SPS signal is coherently integrated usingreceived predicted SPS data comprising SPS sensitivity assistance datareceived over the Ethernet backhaul.
 21. The method of claim 10, whereinusing the external clock signal to generate the internal clock signalcomprises driving an oscillator to a desired frequency that is alignedwith a scaled frequency of the external clock signal to generate theinternal clock signal.